Technical Field
The present invention relates to energy saving technology for an image forming apparatus.
Background Art
Conventionally, an image forming apparatus that stops supplying electric power to its built-in devices to reduce electric power consumption in standby state in which a printing process or a scanning process is not executed is well known.
As an example of this kind of image forming apparatus, an image forming apparatus that wakes up from energy saving mode and transitions to normal mode only if a user is authenticated has been proposed (e.g., JP-2009-104207-A.)
In the technology disclosed in JP-2009-104207-A, an image forming apparatus has a built-in IC tag reader/writer and determines whether or not a user approaches the image forming apparatus by detecting an IC tag held by the user. The IC tag reader/writer reads user information from the IC tag to authenticate the user. Subsequently, if the user is authenticated, the image forming apparatus monitors user operation and transitions to normal mode from sleep mode if it detects user operation.
However, in the technology disclosed in JP-2009-104207-A, the IC tag reader/writer itself consumes considerable power. Also, it is difficult to reduce overall electric power consumption effectively since the image forming apparatus remains in normal mode once it wakes up from sleep mode and transitions to normal mode.
Furthermore, in the technology disclosed in JP-2009-104207-A, it is difficult to maintain adequate security since any user can use the image forming apparatus once an approaching user is authenticated.